1. Field of the Invention
The present invention relates to a solid-electrolyte fuel cell system. More particularly, the invention relates to a solid-electrolyte fuel cell system comprising a plurality of solid-electrolyte fuel cells each including an electrolyte layer, an oxygen electrode applied to one surface of the electrolyte layer, and a fuel electrode applied to the other surface of the electrolyte layer; a plurality of oxygen gas passage devices each defining oxygen-containing gas passages opposed to the oxygen electrode, and having a conductive portion; and a plurality of fuel gas passage devices each defining fuel passages opposed to the fuel electrode, and having a conductive portion; wherein adjacent cells are laminated in a conductive state through the oxygen gas and fuel gas passage devices.
2. Description of the Related Art
Conventionally, an oxygen-containing gas preheated by exhaust gas is supplied in an amount far greater than a theoretical amount necessary for electricity generation, in order to remove heat generated in the cells. Thus, the oxygen-containing gas is used also as cooling gas to cool the cells and maintain the cells at a predetermined temperature.
However, cooling with the oxygen-containing gas produces a great temperature difference between gas inlet and outlet of the cell. This results in a sharp temperature gradient of the cell, leading to its thermal deformation. Thus, there is room for improvement with respect to durability.
Further, since an enormous amount of oxygen-containing gas is supplied, which results in an enormous amount of exhaust, a large and expensive heat exchanger is needed to preheat the oxygen-containing gas with exhaust gas. A great heat loss also occurs through exhaust. Thus, the conventional system has room for improvement from the points of view of economy and installation.